EP1146707B1 - Digitaler erzeuger von modulationssignalen - Google Patents

Digitaler erzeuger von modulationssignalen Download PDF

Info

Publication number
EP1146707B1
EP1146707B1 EP00970235A EP00970235A EP1146707B1 EP 1146707 B1 EP1146707 B1 EP 1146707B1 EP 00970235 A EP00970235 A EP 00970235A EP 00970235 A EP00970235 A EP 00970235A EP 1146707 B1 EP1146707 B1 EP 1146707B1
Authority
EP
European Patent Office
Prior art keywords
level
output
digital modulation
modulation signal
value
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP00970235A
Other languages
English (en)
French (fr)
Other versions
EP1146707A1 (de
EP1146707A4 (de
Inventor
Jun Kinase
Hiroshi Saeki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anritsu Corp
Original Assignee
Anritsu Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anritsu Corp filed Critical Anritsu Corp
Publication of EP1146707A1 publication Critical patent/EP1146707A1/de
Publication of EP1146707A4 publication Critical patent/EP1146707A4/de
Application granted granted Critical
Publication of EP1146707B1 publication Critical patent/EP1146707B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/24—Testing correct operation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0016—Stabilisation of local oscillators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0018—Arrangements at the transmitter end

Definitions

  • the present invention pertains to a digital modulation signal generating apparatus.
  • the present invention relates to a digital modulation signal generating apparatus employing a technique for performing sensitivity measurement or distortion measurement with high precision in the case where a base band signal is modulated in an orthogonal manner by means of a carrier signal, and measurement is performed by employing a signal generating apparatus for generating a digital modulation signal.
  • the invention relates to a digital modulation signal generating apparatus as defined in the preamble of claim 1.
  • a digital modulation signal generating apparatus as defined in the preamble of claim 1.
  • Such an apparatus is known, for example, from JP-A-10-308 718 .
  • OFDM Orthogonal Frequency Division Multiplex modulation system
  • This OFDM modulation system is directed to a system of transmitting modulation waves "m" each having a very low transmission rate with equal intervals in some tens to some thousands of bundles.
  • This digital modulation signal generating apparatus 10 inputs base band signals I and Q output from a base band signal generator 11 and a carrier signal C output from a carrier signal generator 12 into an orthogonal modulator 13, thereby modulating base band signals I and Q in an orthogonal manner by means of a carrier signal C.
  • This orthogonal modulator 13 generates a digital modulation signal Sa of a channel around a carrier frequency "fc", as shown in FIG. 10 .
  • This digital modulation signal Sa is amplified up to a predetermined level by means of an amplifier 14, and then, the amplification output Sb is input to a variable attenuator 15, and is adjusted to a desired level.
  • the digital modulation signal Sc level adjusted at this variable attenuator 15 is output from an output terminal 10a.
  • a measurement object 1 such as communication device or circuit is connected to the output terminal 10a, wherein the sensitivity characteristics or distortion characteristics of the measurement object 1 and the like are measured.
  • the attenuation quantity of the variable attenuator 15 is set to be large, and a level of the digital modulation signal Sc output from the output terminal 10a is set to a very low level (for example, -100 dBm), and is input to the measurement object 1, whereby an error rate of the demodulation signal of the measurement object 1 is measured.
  • a very low level for example, -100 dBm
  • the attenuation quantity of a variable attenuator 15 is set to be small, and a level of the digital modulation signal Sc output from the output terminal 10a is set to a very high level (for example, -10 dBm), and is input to the measurement object 1, whereby a spectrum of an output of the measurement object 1 is observed by means of a spectrum analyzer or the like.
  • a carrier signal C cannot be completely suppressed by a slight non-equivalence of the orthogonal modulator 13, and the residual carrier Ca is contained in the generated digital modulation signal Sa (this is called a carrier leak).
  • the power of one modulation wave is as small as 1 of a component of the modulation frequency relevant to a total power of all the modulation frequencies.
  • an effect of the residual carrier Ca superimposed on one modulation wave becomes very large.
  • this modulation wave is demodulated at the measurement object 1 such as a receiving device, there is a problem that an effect of the residual carrier Ca appears at a demodulation wave, whereby the characteristics of the measurement object 1 can not be precisely measured.
  • the level of a carrier signal C input to the orthogonal modulator 13 is lowered, and conversely, the levels of the base band signals I and Q input to the orthogonal modulator 13 are increased, thereby increasing a level difference ⁇ '.
  • the level of the carrier signal C input to the orthogonal modulator 13 is lowered, there occur problems such as deteriorated switching characteristics of the orthogonal modulator 13 or lowered gain and the like. Thus, the level of the carrier signal C cannot be set to a predetermined level or less.
  • the level of the signal inputted to an amplifier 14 is increased, and thus, the mutual modulation distortion (mainly, third high frequency distortion) generated by non-linearity of the amplifier 14 increases.
  • the mutual modulation distortion mainly, third high frequency distortion
  • the carrier suppression characteristics of the orthogonal modulator itself are improved, and the non-linearity of the orthogonal modulator 13 and amplifier 14 is improved to the maximum.
  • the document JP-A-10-308718 discloses a carrier wave leakage compensation circuit, wherein a first base band signal output from an arithmetic part is converted from a digital signal into a second base band signal of an analog signal by a first D/A converter, and the second base band signal is amplified to the level at the time of maximum channel multiplicity number by a first base band amplifier.
  • the arithmetic part acquires the information of the level to be output from an external circuit through an output terminal corresponding to the channel multiplicity number. When the output level information is acquired, the arithmetic part sets the amplification factor of the first base band amplifier.
  • the document JP-A-11-112364 discloses a transmitting circuit adapted to achieve a desired transmission power.
  • the gains to be set in level varying means are previously registered corresponding to the individual levels at which a transmit wave signal should be sent to a radio transmission.
  • Level setting means find the level at which the transmit wave signal should be transmitted to the radio transmission line according to a communication system and/or a channel setting system applied to the radio transmission line and in a period wherein the transmit wave signal is not transmitted, the gain registered in the storage means is set in the level varying means corresponding to the level.
  • deviations showing a deficiency of a variable width of the level of the transmission level varying means are registered in a deviation storage means dealing with temperature and a deviation storage means dealing with voltage to make it possible to compensate a temperature variation and a variation in source DC voltage.
  • the present invention has been achieved to solve the above-described conventional technical problems. It is an object of the present invention to provide a digital modulation signal generating apparatus capable of making the carrier leak characteristics of the generated digital modulation signal compatible with mutual modulation distortion characteristics.
  • a digital modulation signal generating apparatus of such a type good carrier leak characteristics are required when sensitivity characteristics or the like of a measurement object 1 such, as a receiving device, are measured.
  • a level of a digital modulation signal input to the measurement object 1 is about -100 dBm, which is very low.
  • a level of a digital modulation signal input to the measurement object 1 is about -10 dB, which is very high.
  • the output level is low when the good carrier leak characteristics are required, and the mutual modulation distortion characteristics are not problematic; and the fact that the output level is high when the good mutual modulation distortion characteristics is required, carrier leak characteristics are not problematic.
  • a level diagram inside the apparatus is set so as to improve the carrier leak characteristics.
  • a level diagram inside the apparatus is set so as to improve the mutual modulation distortion characteristics.
  • the carrier leak characteristics and mutual modulation distortion characteristics can be compatible with each other at a high level.
  • FIG. 1 is a block diagram depicting a configuration of a digital modulation signal generating apparatus 20 according to a first embodiment of the present invention, based on the above principle of operation.
  • This digital modulation signal generating apparatus 20 is adopted to output a digital modulation signal in accordance with an OFDM modulation system from an output terminal 20a as in the above described conventional digital modulation signal generating apparatus 10.
  • base band signals Ia and Qa output from a base band signal generator 21 are attenuated by means of variable attenuators 22 and 23 as first level varying means, and are input to an orthogonal modulator 24.
  • variable attenuators 22 and 23 can be employed while they are connected to a variable gain amplifier or a variable attenuator and amplifier in series in the case where a level of the base band signals Ia and Qa output from the base band signal generator 21 is low.
  • the orthogonal modulator 24 orthogonally modulates base band signals Ib and Qb that have passed through the variable attenuators 22 and 23 by means of a carrier signal C output from a carrier signal generator 25, and generates a digital modulation signal Sa of a channel that corresponds to a frequency of the carrier signal.
  • This orthogonal modulator 24 consists of two mixers 24a and 24b, 90-degree phase shifter 24c, and a synthesizer 24d, as shown in FIG. 2 , for example.
  • the base band signal Ib and carrier signal C are input to the mixer 24a, and the base band signal Qb and a carrier signal C' phase-shifted by 90 degrees by means of the phase shifter 24c are input to the mixer 24b.
  • output signals of both of the mixers 24a and 24b are synthesized by means of a synthesizer 24d, and are output as a digital modulation signal Sa in accordance with an OFDM modulation system.
  • This digital modulation signal Sa is amplified by means of an amplifier 27, and then, the amplified output Sb is input to a variable attenuator 28 as second level varying means.
  • a digital modulation signal Sc subjected to attenuation by means of this variable attenuator 28 is output from an output terminal 20a.
  • This variable attenuator 28 is controlled in attenuation quantity by means of a control portion 30 described later in addition to the variable attenuators 22 and 23.
  • Output level specifying means 29 is adopted to specify an output level value A of a digital modulation signal output from the output terminal 20a.
  • the output level value A specified by this output level specifying means 29 is output to the control portion 30.
  • control portion 30 is composed of a microcomputer including CPU, ROM, RAM or the like, for example, and the attenuation quantities Ga and Gb of the variable attenuators 22, 23, and 28 are variably controlled according to the output level value A specified by the output level specifying means 29.
  • This control portion 30 has judgment means 31 and level diagram switching means 32.
  • the judgment means 31 judges whether or not the output level value A specified by the output level specifying means 29 is higher than a predetermined value (or predetermined range).
  • the level diagram switching means 32 based on the output level value A of a digital modulation signal output from the output terminal 20a specified by the output level specifying means 29 and the judgment result obtained by the judgment means 31, attenuation quantity of the variable attenuators 22 and 23 as the first level varying means and the variable attenuator 28 as the second level varying means are set in accordance with the level diagram setting table stored in a ROM as shown in FIG. 12 and the level diagram setting value computed based on the following formula by means of a CPU, for example, so as to be a predetermined attenuation quantity value which makes desired carrier leak characteristics compatible with desired mutual modulation distortion characteristics, respectively.
  • the level diagram switching means 32 is adopted to switch the level diagram inside of the apparatus into a state in which carrier leak characteristic takes precedence over mutual modulation distortion characteristic and a state in which mutual modulation distortion characteristic takes precedence over carrier leak characteristic according to the output level value A of a digital modulation signal output from the output terminal 20a specified by output level specifying means 29 and the judgment result of judgment means 31.
  • control portion 30 set the attenuation quantity of the variable attenuators 22 and 23 to be small so that a level difference between a digital modulation signal of a predetermined channel output from the output terminal 20a and the residual carrier is equal to or larger than a predetermined value.
  • control portion 30 sets an attenuation quantity of the variable attenuator 28 so that a digital modulation signal of a predetermined channel of the specified output level value A is output from the output terminal 20a.
  • control portion 30 sets the attenuation quantity of the variable attenuators 22 and 23 to be large so that a level difference between a digital modulation signal of a predetermined channel output from the output terminal 20a and the mutual modulation distortion is equal to or larger than a predetermined value.
  • control portion 30 sets an attenuation quantity of the variable attenuator 28 so that the digital modulation signal of a predetermined channel of the specified output level value A is output from the output terminal 20a.
  • the presumed numeric value is such that a level of the base band signals Ia and Qa output from a base band signal generator 21 is defined as 0 dBm, a level of a carrier signal outputted from a carrier signal generator 25 is defined as 10 dBm, a carrier suppression ratio of the orthogonal modulator 24 is defined as -70 dB, a gain of the orthogonal modulator 24 (a difference between a level of base band signals Ib and Qb and a level of an output signal Sa) is defined as 10 dB, and a gain of the amplifier 27 is defined as 20 dB.
  • the mutual modulation distortion generated by the orthogonal modulator 24 is very low when its input signal level is lower than -20 dBm, and is gradually deteriorated in excess of -20 dB.
  • the mutual modulation distortion generated by the amplifier 27 is very low when its input signal level is lower than -10 dBm, and is gradually deteriorated in excess of -10 dBm.
  • the judgment means 31 judges whether or not the output level value A specified from the output level specifying means 29 is higher than -50 dBm which is a predetermined value.
  • the output level value A is specified as -100 (dBm), for example, by the output level specifying means 29.
  • the judgment means 31 judges that the specified output level value A is lower than -50 (dBm) that is a predetermined value.
  • a level difference (hereinafter, referred to as a carrier leak ratio) between a total level of a digital modulation signal required during measurement of such sensitivity characteristics and the residual carrier is 50 dB or more.
  • That a level difference between a total level and the residual carrier is secured to be 50 dB or more denotes that, in OFDM modulation of 1,000 modulation waves, for example, a level of one modulation wave is 1/1,000 of the total level, and thus, a level difference from one modulation wave superimposed on the residual carrier is ensured by 20 dB or more.
  • a difference between a total level of a digital modulation signal required for measurement of distortion characteristics such as an amplifier or mixer and the like and a total level of a mutual modulation distortion (hereinafter, referred to as adjacent channel leak ratio) is 70 dB or more.
  • the level diagram switching means 32 sets the level diagram inside of the apparatus so that a level difference between a digital modulation signal of a predetermined channel output from the output terminal 20a and the residual carrier is increased, and the digital modulation signal of the output level value A specified by the output level specifying means 29 is output from the output terminal 20a.
  • the attenuation quantity Ga of the variable attenuators 22 and 23 is set to 10 dB which is comparatively small, whereby the input level of the base band signals I and Q relevant to the orthogonal modulator 24 becomes -10 dBm.
  • the digital modulation signal, mutual modulation distortion, and residual carrier are shown as a total level.
  • This digital modulation signal Sa is amplified to 20 dBm by means of the amplifier 27, and the amplified output Sb is input to the variable attenuator 28.
  • the residual carrier Ca as well as digital modulation signal Sa is amplified to -40 dBm by means of the amplifier 27, and attenuation of 120 dB is received by the variable attenuator 28.
  • the residual carrier Cc attenuated to -160 dBm is output from the output terminal 20a.
  • a level difference from one modulation wave superimposed on the residual carrier is ensured by 20 dB or more, denotes that a level difference between a total level and the residual carrier is secured to be more than 50 dB or more.
  • the level diagram from the base band signal generator 21 to an output of the amplifier 27 is such that the output level value A specified by the output level specifying means 29 does not change in a range which is lower than -50 (dBm), and changes according to the output level value A specified by the attenuation quantity of the variable attenuator 28.
  • the carrier leak ratio ⁇ relevant to a total level is ensured as 60 dB.
  • the level of the residual carrier Cc is very low relevant to the level of the digital modulation signal Sc output from the output terminal 20a, as shown in FIG. 4 , by the level diagram switching means 32.
  • the sensitivity measurement relevant to the measurement object 1 such as a receiving device can be precisely performed without being affected by the residual carrier Cc.
  • the input signal level of the orthogonal modulator 24 is higher than -20 dBm.
  • a mutual modulation distortion Ra is generated at a comparatively high level (-50 dBm) with an output of the orthogonal modulator 24.
  • the input signal level of the amplifier 27 is higher than - 10 dBm, and thus, a mutual modulation distortion Rb of a level (-20 dBm) higher than such a gain is generated.
  • this mutual modulation distortion Rb is attenuated by means of the variable attenuator 28, and a mutual modulation distortion Rc of -140 dBm is output from the output terminal 20a.
  • This mutual modulation distortion Rc leaks not only into a predetermined channel but also into the adjacent channels to this predetermined channel, as shown in FIG. 4 .
  • the output level value A is specified as -10 (dBm), for example, by the output level specifying means 29.
  • judgment means 31 judges that the output level value A specified by -50 (dBm) that is a predetermined value is high.
  • the level diagram switching means 32 sets the level diagram inside of the apparatus so that a mutual modulation distortion is reduced, and the digital modulation signal of the specified level value A is output from the output terminal 20a.
  • the attenuation quantity of the variable attenuators 22 and 23 becomes 30 dB, whereby the input level of the base band signals Ib and Qb relevant to the orthogonal modulator 24 is set to -30 dBm.
  • This digital modulation signal Sa is amplified to 0 dBm by means of the amplifier 27, and the amplified output Sb is input to the variable attenuator 28.
  • the level of the digital modulation signal Sa input to the amplifier 27 is lower than -10 dBm, and thus, an increase in mutual modulation distortion caused by the amplifier 27 can be almost ignored.
  • This mutual modulation distortion is attenuated by 10 dB by means of the variable attenuator 28, whereby a mutual modulation distortion Rc of -90 dBm is generated at the output terminal 20a.
  • a level diagram from the base band signal generator 21 to an output of the amplifier 27 does not change in a range in which the output level value A specified by the output level specifying means 29 is higher than -50 (dBm).
  • the measurement of characteristics of an amplifier or mixer and the like relevant to the measurement object 1 can be precisely performed without being affected by the mutual modulation distortion Rc.
  • the input signal level of the orthogonal modulator 24 is as low as -30 dBm.
  • the carrier leak ratio ⁇ ' relevant to a level of a modulation wave superimposed on the residual carrier is deteriorated as 10 dB, and the residual carrier Cc at its comparatively large level is generated as shown in FIG. 6 .
  • the carrier leak ratio a relevant to a total level is ensured by 40 dB, and thus, the level of the residual carrier Cc is sufficiently smaller than a total level.
  • the input signal level of the orthogonal modulator 24 and amplifier 27 is determined by means of the variable attenuators 22 and 23 provided at the front stage of the orthogonal modulator 24.
  • a variable attenuator 26 as third level varying means is provided between the orthogonal modulator 24 and the amplifier 27, as shown in FIG. 7 .
  • variable attenuator 26 is controlled by the level diagram switching means 32 together with the variable attenuators 22 and 23 as the first level varying means and the variable attenuator 28 as second level varying means.
  • variable attenuator 26 is provided at the front stage of the amplifier 27, whereby the variable attenuators 22 and 23 can be used independently for input level variation of the orthogonal modulator 24 and the variable attenuator 26 can be used for input level variation of the amplifier 27.
  • the level control corresponding to each of the dynamic ranges of the orthogonal modulator 24 and the amplifier 27 can be performed.
  • the digital modulation signal generating apparatus 20 when the dynamic range of the amplifier 27 is narrower than that of the orthogonal modulator 24, the range is restricted to the dynamic range of the amplifier 27, and the carrier leak ratio cannot be increased because the input level of the orthogonal modulator 24 cannot be increased.
  • variable attenuator 26 is provided at the front stage of the amplifier 27, whereby the carrier leak ratio can be further increased.
  • the attenuation quantities Ga, Gb, and Gc of the variable attenuators 22 and 23 as the first level varying means, the variable attenuator 26 as second level means, and the variable attenuator 28 as third level varying means are set in accordance with the level diagram setting table stored in a ROM as shown in FIG. 13 , for example, and the level diagram setting value computed based on the following formula by the CPU so as to be a predetermined attenuation quantity value which makes compatible desired carrier leak characteristics and desired mutual modulation distortion characteristics.
  • a presumed numeric value is selected as in the digital modulation signal generating apparatus 20 according to the first embodiment.
  • the presumed numeric value is such that a level of the base band signals Ia and Qa output from the base band signal generator 21 is defined as 0 dBm; a level of a carrier signal outputted from the carrier signal generator 25 is defined as 10 dBm; a carrier suppression ratio of the orthogonal modulator 24 is defined as -70 dB; a gain of the orthogonal modulator 24 (a difference between a level of the base band signals Ib and Qb and a level of an output signal Sa) is defined as 10 dB; and a gain of the amplifier 27 is defined as 20 dB.
  • the mutual modulation distortion generated by the orthogonal modulator 24 is very low when its input signal level is lower than -20 dBm, and is gradually deteriorated in excess of -20 dBm.
  • the mutual modulation distortion generated by the attenuator 27 is very low when its input signal level is lower than -10 dBm, and is gradually deteriorated in excess of -10 dBm.
  • the judgment means 31 judges whether or not the level value A specified from the output level specifying means 29 is higher than -50 dBm that is a predetermined value.
  • the output level value A is specified as -100 (dBm), for example, by the output level specifying means 29.
  • the judgment means 31 judges that the output level value A specified by -50 (dBm) that is a predetermined value is low.
  • the level diagram switching means 32 sets the level diagram inside of the apparatus so that the carrier leak ratio is large, and a digital modulation signal of the specified output level value A is output from the output terminal 20a.
  • the level diagram switching means 32 sets the attenuation quantity Ga of the variable attenuators 22 and 23 to 0 dB, as shown in FIG. 8A and FIG. 8B , and set to 0 dBm an input level of the base band signals Ib and Qb relevant to the orthogonal modulator 24.
  • a total level of the digital modulation signal Sa output from the orthogonal modulator 24 becomes 10 dBm, and a level of the residual carrier Ca becomes -60 dBm.
  • the digital modulation signal Sa and the residual carrier Ca are input to the variable attenuator 26.
  • the level diagram switching means 32 sets the attenuation quantity Gb of the variable attenuator 26 to 20 dB, whereby the digital modulation signal Sa is attenuated to -10 dBm, the residual carrier Ca is attenuated to -80 dBm, and these signal and carrier are input to the attenuator 27.
  • the digital modulation signal Sb and residual carrier Cb attenuated by means of this variable attenuator 26 are amplified to 10 dBm and -70 dBm, respectively, by means of the attenuator 27, and the amplified outputs Sc and Cc are input to the variable attenuator 28.
  • the level diagram switching means 32 sets the attenuation quantity Gc of the variable attenuator 28 to 110 dB, and sets a level of the digital modulation signal Sd output from the output terminal 20a to -100 dBm that corresponds to the specified output level value A, whereby the level of the residual carrier Cd output from the output terminal 20a is attenuated to -170 dBm.
  • a carrier leak ratio ⁇ relevant to a total level at the output terminal 20a becomes 70 dB
  • a carrier leak ratio ⁇ ' relevant to a level of the modulation waves superimposed on the residual carrier becomes 40 dB.
  • the digital modulation signal generating apparatus 20' according to the second embodiment there can be obtained the carrier leak ratio which is even higher than that of the digital modulation signal generating apparatus 20 according to the first embodiment.
  • the sensitivity measurement relevant to the measurement object 1 such as receiving device can be performed more precisely.
  • the input signal level of the orthogonal modulator 24 is higher, and the mutual modulation distortion Ra is generated at a higher level (-35 dBm).
  • the input signal level of the attenuator 26 is lowered to -10 dBm by means of the variable attenuator 27.
  • the generation of the mutual modulation distortion caused by the attenuator 27 itself can be almost ignored.
  • the mutual modulation distortion Rc of the output of the attenuator 27 can become -30 dBm, which is lower than a case of the digital modulation signal generating apparatus 20.
  • the adjacent channel leak ratio ⁇ at the output terminal 20a becomes 40 dB in the same manner as in the digital modulation signal generating apparatus 20, and an extreme increase in mutual modulation distortion caused by an input level increase can be suppressed.
  • the output level value A is specified as -10 (dBm) by the output level specifying means 29.
  • the judgment means 31 judges that the level value A specified by -50 (dBm) that is a predetermined value is high.
  • the level diagram switching means 32 sets a level diagram inside of the apparatus so that the mutual modulation distortion is reduced, and a digital modulation signal of the specified output level value A is output from the output terminal 20a.
  • the level diagram switching means 32 sets the attenuation quantity Ga of the variable attenuators 22 and 23 to 30 dB, as shown in FIG. 9A and FIG. 9B , whereby the input level of the base band signals Ib and Qb relevant to the orthogonal modulator 24 becomes -30 dBm.
  • the total level of the digital modulation signal Sa outputted from the orthogonal modulator 24 becomes -20 dBm, and the mutual modulation distortion Ra of the orthogonal modulator 24 becomes -100 dBm, similarly.
  • This digital modulation signal Sa and mutual modulation distortion Ra are input to the variable attenuator 26.
  • the level diagram switching means 32 sets the attenuation quantity of the variable attenuator 26 to 0 dB, whereby the digital modulation signal Sb of -20 dBm and the mutual modulation distortion Ra of -100 dBm are input to the amplifier 27.
  • This digital modulation signal Sb is amplified to 0 dBm by means of the amplifier 27, and its amplified output Sc is input to the variable attenuator 28.
  • the input signal level of the amplifier 27 is as low as -20 dBm, and thus, the mutual modulation distortion generated by the amplifier 27 itself can be ignored.
  • the mutual modulation distortion Rc of -80 dBm is output, and is input to the variable attenuator 28.
  • the level diagram switching means 32 sets the attenuation quantity Gc of the variable attenuator 28 to 10 dB, and the level of the digital modulation signal Sd output from the output terminal 20a becomes -10 dBm that corresponds to the specified output level value A.
  • the mutual modulation distortion Rd output from the output terminal 20a becomes -90 dBm due to the attenuation caused by the variable attenuator 28.
  • the adjacent channel leak ratio ⁇ at the output terminal 20a becomes 80 dB, and measurement of the distortion characteristics of an amplifier or mixer and the like relevant to the measurement object 1 can be precisely performed without being affected by this mutual modulation distortion.
  • the input signal level of the orthogonal modulator 24 is low, and thus, the levels of the residual carriers Ca, Cb, Cc, and Cd are high.
  • the carrier leak ratio ⁇ relevant to a total level is ensured by 40 dB.
  • an effect of measurement of distortion characteristics relevant to the measurement object 1 such as amplifier or mixer with respect to a signal total level can be almost ignored.
  • the judgment means 31 judges whether or not the output level value A specified from the output level specifying means 29 is higher than a predetermined value (-50 dBm) so that the level diagram in the apparatus is varied.
  • a range of -40 to -60 (dBm) is defined as a predetermined range, and the specified output level value A is lower than this predetermined range
  • a level diagram with carrier leak characteristics taking precedence over any other characteristics in the same way as previously there may be employed a level diagram with mutual modulation distortion characteristics taking precedence over any other characteristics in the same manner as previously.
  • the attenuation quantity (or gain) of the variable attenuators 22 and 23 in the case of the digital modulation signal generating apparatus 20 and the attenuation quantity (or gains) of the variable attenuators 22 and 23, and the attenuation quantity of the variable attenuator 26 in the case of digital modulation signal generating apparatus 20' are set to values between a value obtained when carrier leak characteristics precedes any other characteristics and a value obtained when mutual modulation distortion characteristics precedes any other characteristics, whereby the carrier leak characteristics and mutual modulation distortion characteristics are controlled to be placed in a comparatively good state.
  • a digital modulation signal generating apparatus wherein first level varying means is provided between a base band signal generator and an orthogonal modulator; second level varying means is provided between an amplifier and an output terminal; it is judged whether or not an output level value specified by output level specifying means is higher than a predetermined value or a predetermined range; when it is judged that the specified output level value is lower than the predetermined value or the predetermined range, the first level varying means is set so that a level difference between a digital modulation signal output from an output terminal and a residual carrier is equal to or larger than a predetermined value, and an attenuation quantity of the second level varying means is set so that a digital modulation signal of the specified output level value is output from an output terminal; when the specified output level value is higher than the predetermined value or the predetermined range, the first level varying means is set so that a level difference between a digital modulation signal output from an output terminal and a mutual modul
  • a digital modulation signal can be output such that carrier leak characteristics suitable to such sensitivity measurement are very good.
  • a digital modulation signal can be output such that mutual modulation distortion characteristics suitable to the distortion characteristics or the like are very good.
  • carrier leak characteristics and mutual modulation distortion characteristics can be compatible with each other at a high level.
  • a digital modulation signal generating apparatus wherein first level varying means is provided between a base band signal generator and an orthogonal modulator; third level varying means is provided between an orthogonal modulator and a modulator; second level varying means is provided between an amplifier and an output terminal; it is judged whether or not an output level value specified by output level specifying means is higher than a predetermined value or a predetermined range; when it is judged that the specified output level value is lower than the predetermined value or predetermined range, the first level varying means is set so that a level difference between a digital modulation signal output from an output terminal and a residual carrier is equal to or larger than the predetermined value or range, and the second level varying means and third level varying means are set so that the digital modulation signal of the specified output level value is output from the output terminal; and when it is judged that the specified output level value is higher than the predetermined value or predetermined range, the first level varying means and third level varying means are set
  • a digital modulation signal can be output such that carrier leak characteristics suitable to the sensitivity measurement or the like are very good.
  • a digital modulation signal can be output such that mutual modulation distortion characteristics suitable to those distortion characteristics or the like are very good.
  • independent level varying means at the front stage of each of the orthogonal modulator and amplifier.
  • a digital modulation signal generating apparatus capable of making compatible with each other the carrier leak characteristics of the generated digital modulation signal and the mutual modulation distortion characteristics at a high level.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Amplifiers (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Claims (6)

  1. Signalerzeugungsvorrichtung für digitale Modulationssignale, die folgendes ausweist:
    - einen Basisbandsignalgenerator (21);
    - einen Trägersignalgenerator (25);
    - einen Orthogonalmodulator (24), um nach dem Empfang eines von dem Basisbandsignalgenerator (21) ausgegebenen Basisbandsignals und eines von dem Trägersignalgenerator (25) ausgegebenen Trägersignals ein digitales Modulationssignal eines vorbestimmten Kanals zu erzeugen, der einer Frequenz des Trägersignals entspricht;
    - einen Verstärker (27) zum Verstärken eines von dem Orthogonalmodulator (24) erzeugten digitalen Modulationssignals;
    - einen Ausgangsanschluß (20a) zum Ausgeben eines von dem Verstärker (27) verstärkten digitalen Modulationssignals;
    - eine erste Pegeländerungseinrichtung (22, 23), die zwischen dem Basisbandsignalgenerator (21) und dem Orthogonalmodulator (24) vorgesehen ist, um einen Pegel des Basisbandsignals zu variieren, und um ein Ausgangssignal dem Orthogonalmodulator (24) zuzuführen;
    - eine zweite Pegeländerungseinrichtung (28), die zwischen dem Verstärker (27) und dem Ausgangsanschluß (20a) vorgesehen ist, um einen Pegel eines Ausgangssignals des Verstärkers (27) zu variieren, und um ein Ausgangssignal von dem Ausgangsanschluß (20a) auszugeben;
    - eine Ausgangspegel-Spezifizierungseinrichtung (29) zum Spezifizieren eines Ausgangspegelwertes eines digitalen Modulationssignals, das von dem Ausgangsanschluß (20a) ausgegeben wird;
    - eine Beurteilungseinrichtung (31), um zu entscheiden, ob ein Ausgangspegelwert eines digitalen Modulationssignals, das von der Ausgangspegel-Spezifierungseinrichtung (29) spezifiziert worden ist, höher ist als ein vorgegebener Wert; und
    - eine Pegeldiagramm-Umschalteinrichtung (32) zum Vorgeben eines Dämpfungsgrades der ersten Pegeländerungseinrichtung (22, 23) und eines Dämpfungsgrades der zweiten Pegeländerungseinrichtung (28), so daß ein digitales Modulationssignal, das von dem Ausgangsanschluß (20a) ausgegeben wird, einen vorbestimmten Dämpfungsgradwert besitzt, der eine gewünschte Trägerrestcharakteristik mit einer gewünschten Intermodulations-Verzerrungscharakteristik kompatibel macht, und zwar auf der Basis des Ausgangspegelwertes eines digitalen Modulationssignals, das von der Ausgangspegel-Spezifizierungseinrichtung (29) spezifiziert worden ist, und des Beurteilungsergebnisses, das von der Beurteilungseinrichtung (31) geliefert worden ist,
    dadurch gekennzeichnet,
    daß die Pegeldiagramm-Umschalteinrichtung (32) dazu ausgelegt ist, den Dämpfungsgrad der ersten Pegeländerungseinrichtung (22, 23) so vorzugeben, daß eine Pegeldifferenz zwischen einem digitalen Modulationssignals eines vorgegebenen Kanals, das von dem Ausgangsanschluß (20a) ausgegeben wird, und einem Trägerrest gleich einem oder größer als ein vorbestimmter Wert für den Fall ist, in welchem von der Beurteilungseinrichtung (31) entschieden worden ist, daß ein Ausgangspegelwert, der von der Ausgangspegel-Spezifierungseinrichtung (29) spezifiziert worden ist, niedriger ist als der vorbestimmte Wert, und den Dämpfungsgrad der zweiten Pegeländerungseinrichtung (28) so vorzugeben, daß ein digitales Modulationssignal eines vorbestimmten Kanals mit einem Ausgangspegelwert, der von der Ausgangspegel-Spezifierungseinrichtung (29) spezifiziert worden ist, von dem Ausgangsanschluß (20a) ausgegeben wird, und daß die Pegeldiagramm-Umschalteinrichtung (32) dazu ausgelegt ist, den Dämpfungsgrad der ersten Pegeländerungseinrichtung (22, 23) so vorzugeben, daß eine Pegeldifferenz zwischen einem digitalen Modulationssignal eines vorbestimmten Kanals, das von dem Ausgangsanschluß (20a) ausgegeben wird, und einer Intermodulationsverzerrung gleich einem oder größer als ein vorbestimmter Wert in einem Falle ist, in welchem von der Beurteilungseinrichtung (31) entschieden worden ist, daß ein Ausgangspegelwert, der von der Ausgangspegel-Spezifizierungseinrichtung (29) spezifiziert worden ist, höher ist als der vorbestimmte Wert, und den Dämpfungsgrad der zweiten Pegeländerungeinrichtung (28) so vorzugeben, daß ein digitales Modulationssignal eines vorbestimmten Kanals mit einem Ausgangspegelwert, der von der Ausgangspegel-Spezifierungseinrichtung (29) spezifiziert worden ist, von dem Ausgangsanschluß (20a) ausgegeben wird.
  2. Vorrichtung nach Anspruch 1,
    dadurch gekennzeichnet,
    daß die Signalerzeugungsvorrichtung (20) für digitale Modulationssignale ferner eine Berechnungseinrichtung (30) aufweist, um einen vorbestimmten Dämpfungsgradwert für die erste Pegeländerungseinrichtung (22, 23) und die zweite Pegeländerungseinrichtung (28) zu berechnen, der von der Pegeldiagramm-Umschalteinrichtung (32) vorgegeben wird, und zwar auf der Basis eines Ausgangspegelwertes eines digitalen Modulationssignals, der zumindest von der Ausgangspegel-Spezifizierungseinrichtung (29) spezifiziert wird, und des Beurteilungsergebnisses, das von der Beurteilungseinrichtung (31) geliefert wird.
  3. Vorrichtung nach Anspruch 1,
    dadurch gekennzeichnet,
    daß die Signalerzeugungsvorrichtung (20) für digitale Modulationssignale ferner eine Speichereinrichtung (30) aufweist, um im voraus in einem Tabellenformat einen vorbestimmten Dämpfungsgradwert für die erste Pegeländerungseinrichtung (22, 23) und die zweite Pegeländerungseinrichtung (28) zu speichern, die von der Pegeldiagramm-Umschalteinrichtung (29) vorgegeben werden.
  4. Vorrichtung nach Anspruch 1,
    dadurch gekennzeichnet,
    daß die Signalerzeugungsvorrichtung für digitale Modulationssignale ferner eine dritte Pegeländerungseinrichtung (26) ausweist, die zwischen dem Orthogonalmodulator (24) und dem Verstärker (27) vorgesehen ist, um einen Pegel eines digitalen Modulationssignals zu variieren, der von dem Orthogonalmodulator (24) ausgegeben wird, und um das digitale Modulationssignal in den Verstärker (27) einzugeben,
    daß die Pegeldiagramm-Umschalteinrichtung (32) dazu ausgelegt ist, den Dämpfungsgrad der ersten Pegeländerungseinrichtung (22, 23) so vorzugeben, daß eine Pegeldifferenz zwischen einem digitalen Modulationssignal eines vorbestimmten Kanals, das von dem Ausgangsanschluß (20a) ausgegeben wird, und einem Trägerrest gleich einem oder größer als ein vorbestimmter Wert in dem Falle ist, in welchem von der Beurteilungseinrichtung (31) entschieden worden ist, daß ein Ausgangspegelwert, der von der Ausgangspegel-Spezifizierungseinrichtung (29) spezifiziert worden ist, niedriger ist als der vorbestimmte Wert, und einen Dämpfungsgrad der dritten Pegeländerungseinrichtung (26) mit einem großen Wert vorzugeben, so daß eine Pegeldifferenz zwischen einem digitalen Modulationssignal eines vorbestimmten Kanals, der von dem Ausgangsanschluß (20a) ausgegeben wird, und einem Trägerrest gleich einem oder größer als ein vorbestimmter Wert ist, und den Dämpfungsgrad der zweiten Pegeländerungseinrichtung (28) so vorzugeben, daß ein digitales Modulationssignal eines vorbestimmten Kanals mit einem Ausgangspegelwert, der von der Ausgangspegel-Spezifizierungseinrichtung (29) spezifiziert wird, von dem Ausgangsanschluß (20a) ausgegeben wird,
    und daß die Pegeldiagramm-Umschalteinrichtung (32) dazu ausgelegt ist, den Dämpfungsgrad der ersten Pegeländerungseinrichtung (22, 23) so vorzugeben, daß eine Pegeldifferenz zwischen einem digitalen Modulationssignal eines vorbestimmten Kanals, der von dem Ausgangsanschluß (20a) ausgegeben wird, und einer Intermodulationsverzerrung gleich einem oder größer als ein vorbestimmter Wert in dem Falle ist, in welchem von der Beurteilungseinrichtung (31) entschieden worden ist, daß ein Ausgangspegelwert, der von der Ausgangspegel-Spezifizierungseinrichtung (29) spezifiziert worden ist, höher ist als der vorbestimmte Wert, und den Dämpfungsgrad der dritten Pegeländerungseinrichtung (26) so vorzugeben, daß eine Pegeldifferenz zwischen einem digialen Modulationssignal eines vorbestimmten Kanals, das von dem Ausgangsanschluß (20a) ausgegeben wird, und einer Intermodulationsverzerrung gleich einem oder größer als ein vorbestimmter Wert ist, und den Dämpfungsgrad der zweiten Pegeländerungeinrichtung (28) so vorzugeben, daß ein digitales Modulationssignal eines vorbestimmten Kanals mit dem Ausgangspegelwert, der von der Ausgangspegel-Spezifizierungseinrichtung (29) spezifiziert worden ist, von dem Ausgangsanschluß (20a) ausgegeben wird.
  5. Vorrichtung nach Anspruch 4,
    dadurch gekennzeichnet,
    daß die Signalerzeugungsvorrichtung für digitale Modulationssignale ferner eine Berechnungseinrichtung (30) aufweist, um einen vorbestimmten Dämpfungsgradwert für die erste Pegeländerungseinrichtung (22, 23), für die zweite Pegeländerungseinrichtung (28) und für die dritte Pegeländerungseinrichtung (26) zu berechnen, der von der Pegeldiagramm-Umschalteinrichtung (32) vorgegeben ist, und zwar auf der Basis eines Ausgangspegelwertes eines digitalen Modulationssignals, das zumindest von der Ausgangspegel-Spezifizierungseinrichtung (29) spezifiziert worden ist, und des Beurteilungsergebnisses, das von der Beurteilungseinrichtung (31) geliefert wird.
  6. Vorrichtung nach Anspruch 4,
    dadurch gekennzeichnet,
    daß die Signalerzeugungsvorrichtung für digitale Modulationssignale ferner eine Speichereinrichtung (30) aufweist, um im voraus in einem Tabellenformat einen vorbestimmten Dämpfungsgradwert für die erste Pegeländerungseinrichtung (22, 23), für die zweite Pegeländerungseinrichtung (28), und für die dritte Pegeländerungseinrichtung (26) zu speichern, die von der Pegeldiagramm-Umschalteinrichtung (32) vorgegeben werden.
EP00970235A 1999-11-05 2000-10-31 Digitaler erzeuger von modulationssignalen Expired - Lifetime EP1146707B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP31590399 1999-11-05
JP31590399A JP4289744B2 (ja) 1999-11-05 1999-11-05 信号発生装置
PCT/JP2000/007660 WO2001035589A1 (fr) 1999-11-05 2000-10-31 Generateur de signaux de modulation numeriques

Publications (3)

Publication Number Publication Date
EP1146707A1 EP1146707A1 (de) 2001-10-17
EP1146707A4 EP1146707A4 (de) 2006-08-23
EP1146707B1 true EP1146707B1 (de) 2010-02-24

Family

ID=18071004

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00970235A Expired - Lifetime EP1146707B1 (de) 1999-11-05 2000-10-31 Digitaler erzeuger von modulationssignalen

Country Status (5)

Country Link
US (1) US6904099B1 (de)
EP (1) EP1146707B1 (de)
JP (1) JP4289744B2 (de)
DE (1) DE60043880D1 (de)
WO (1) WO2001035589A1 (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1962438A1 (de) * 2007-02-22 2008-08-27 Sony Deutschland GmbH Datenübertragungsverfahren und Modem

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH032716A (ja) 1989-05-30 1991-01-09 Sony Corp 光学的ローパスフイルタ
JPH032716U (de) * 1989-05-31 1991-01-11
JPH05251943A (ja) * 1992-03-05 1993-09-28 Nec Corp 送信電力制御装置
JPH05267959A (ja) * 1992-03-18 1993-10-15 Iwatsu Electric Co Ltd 出力振幅制御装置
JP2852292B2 (ja) * 1997-05-06 1999-01-27 埼玉日本電気株式会社 搬送波リーク補償回路
JPH11112364A (ja) * 1997-09-30 1999-04-23 Fujitsu Ltd 送信回路
JPH11284672A (ja) * 1998-03-27 1999-10-15 Sony Corp デジタル変調信号発生装置
JP2990507B2 (ja) * 1998-05-27 1999-12-13 アンリツ株式会社 信号発生装置および隣接・隣々接チャネル漏洩電力測定システム
JP2000323999A (ja) * 1999-05-13 2000-11-24 Denso Corp 送信電力制御回路

Also Published As

Publication number Publication date
WO2001035589A1 (fr) 2001-05-17
JP2001136216A (ja) 2001-05-18
US6904099B1 (en) 2005-06-07
EP1146707A1 (de) 2001-10-17
DE60043880D1 (de) 2010-04-08
JP4289744B2 (ja) 2009-07-01
EP1146707A4 (de) 2006-08-23

Similar Documents

Publication Publication Date Title
US6353359B1 (en) Training scheme for high efficiency amplifier
KR100362131B1 (ko) 시분할다중액세스무선통신시스템내의기지국을테스트하는방법및장치
US7206557B2 (en) Method and apparatus for suppressing local oscillator leakage in a wireless transmitter
US8805311B2 (en) Filter unit, mobile communication terminal test system, and mobile communication terminal test method
US7496063B2 (en) Time division multiplexing radio system for controlling transmission power
EP1067676B1 (de) Verfahren zur breitbandigen Linearisierung von Leistungsverstärkern
MX2010013967A (es) Metodo para probar un receptor de frecuencia de radio (rf) para proporcionar datos de correccion de energia.
JPH0479406A (ja) 電力増幅装置及び送信装置
KR20040085962A (ko) 무선 송수신장치에서 자가 보상장치 및 방법
KR20050116138A (ko) Ｉ/ｑ 미스매칭 보상 방법을 이용하는 송수신기
EP1137174A2 (de) System zur automatischen Verstärkungsregelung
US9287906B2 (en) Transmission apparatus and wireless signal transmission method
EP0845885A2 (de) Vorrichtung zum Erzeugen eines modulierten Signals für ein digitales Kommunikationssystem mit Fadingsimulator
US7502599B2 (en) Cartesian loop transmitter and method of adjusting an output level of such transmitter
EP1339248B1 (de) Verfahren und einrichtung zur verstärkungsentzerrung auf der grundlage einer breitband-mehrträger-basisstation
US9413570B2 (en) Mobile terminal test device and mobile terminal test method
US20070286308A1 (en) System and method for modulated signal generation method using two equal, constant-amplitude, adjustable-phase carrier waves
EP1146707B1 (de) Digitaler erzeuger von modulationssignalen
JPH06303045A (ja) 負帰還増幅器
US7209715B2 (en) Power amplifying method, power amplifier, and communication apparatus
AU647133B2 (en) Radio test loop for a radio transceiver
JP2852294B2 (ja) 送信機
JP3048760B2 (ja) 時分割多重伝送方式ディジタル変調無線電話機
JP2990507B2 (ja) 信号発生装置および隣接・隣々接チャネル漏洩電力測定システム
KR100241895B1 (ko) 디지털셀룰라시스템에서의 타가입자잡음 발생장치 및 그를 이용한 가입자 부하인가방법

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20010801

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE GB

A4 Supplementary search report drawn up and despatched

Effective date: 20060724

RIC1 Information provided on ipc code assigned before grant

Ipc: H04L 27/20 20060101AFI20010518BHEP

Ipc: H04J 11/00 20060101ALI20060719BHEP

Ipc: G01R 31/28 20060101ALI20060719BHEP

17Q First examination report despatched

Effective date: 20061122

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE GB

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 60043880

Country of ref document: DE

Date of ref document: 20100408

Kind code of ref document: P

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20101125

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20101230

Year of fee payment: 11

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20101031

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20101031

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130501

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 60043880

Country of ref document: DE

Effective date: 20130501